The present invention relates generally to the golf clubs and, more particularly, to golf club heads.
Modern golf clubs have typically been classified as either woods, irons or putters. The term xe2x80x9cwoodxe2x80x9d is a historical term that is still commonly used, even for golf clubs that are constructed of steel, titanium, fiberglass or other more exotic materials, to name a few. The term xe2x80x9cironxe2x80x9d is also a historical term that is still commonly used, even though those clubs are not typically constructed of iron, but are rather constructed of many of the same materials used to construct xe2x80x9cwoodsxe2x80x9d.
Many advancements have been achieved, particularly over the past couple of decades, to make it easier to hit longer and straighter shots with woods and irons. In general, golf clubs are now designed to be more forgiving, so that shots that are struck less than perfectly will still have fairly consistent distance and directional control. Moreover, club heads now commonly are constructed of combinations of materials, to attempt to optimize the ball flight desired by a particular type of player.
One particular improvement that relates to irons is the use of perimeter weighting, whereby a disproportionate amount of the total weight of a club head is positioned behind and proximate the perimeter of the club head""s striking face, thereby creating a cavity immediately behind the striking face. The cavity is formed by the club face wall and the weight that is placed around and behind the club face. This type of club is typically referred to as a xe2x80x9ccavity backxe2x80x9d iron. By moving the weight peripherally away from the center of gravity (CG) of the club head, the club is made to be more forgiving on off-center hits, resulting in more consistent distance and directional control. Further, perimeter weighting generally increases the moment of inertia about the club""s CG, resulting in less twisting due to off-center hits, and more accurate shots.
There are so-called xe2x80x9chollowxe2x80x9d irons that incorporate a rear wall that is spaced from the front striking face. This also increases the moment of inertia about the club""s CG and is found to benefit some higher handicap golfers. Some hollow irons more closely resemble fairway woods in cross-sectional shape, while other hollow irons may resemble cavity back irons in their cross-section.
Another improvement is the use of lighter and stronger materials, which enables club designers to move the CG to an optimal location on a wood or iron. Such a movement can make the club either easier to hook or to fade, if the movement is made either closer to or farther from the hosel. Similarly, if the CG is moved higher or lower with respect to the club face, the golf ball launch conditions can be altered. For instance, lowering the CG generally makes it easier to get the ball airborne for either an iron or a wood. Conversely, raising the CG promotes a more boring ball flight that generally leaves the club face at a lower launch angle.
Generally, it has been shown that it can be advantageous for players with higher handicaps to use clubs with a lower CG. This is especially true for long irons, such as for example a 3-iron. Club designers have responded to this prospective advantage by lowering the CG of both woods and irons for clubs intended for higher handicap players. The most common way that this has been accomplished for irons is to move as much weight as possible to the area proximate the sole of the club. This results in a concentration of weight proximate the sole. Often, for these types of irons, the transition from the cavity to the weight on the sole is abrupt, compared to traditional irons having a smoother transition. When viewing a cross-section of the lower portion of the club face, a dramatic change in the thickness of the face nearer the sole often is apparent in such sole-weighted club heads.
While it is recognized that the lower CG of the improved clubs can be beneficial, such a lowering can have negative side effects. First, the concentrated mass proximate the sole can increase the stiffness of the club head. This can cause a noticeable change in the club""s feel. Feel is a term that is generally used by skilled practitioners to denote a subjective expression of the way a club feels to one""s hands when striking a golf ball, or the way it sounds. Feel is generally perceived as audible to tactile feedback to the golfer. Different sensations due to striking the ball in different locations on the club face may make a club less desirable to a potential user.
Second, the weight concentration proximate the sole can lead to different levels of flex at different points on the club face. The area of the face proximate the thickest portion of the sole is likely to flex less than the area proximate the inner areas of the striking face. Such a change in flex can adversely affect performance.
Third, the weight concentration can lead to excess vibration, which can adversely affect the feel of the golf club, including the sound made by the club.
It should be appreciated from the foregoing description that there is a need for an improved golf club head that creates a more consistent flex when striking the ball, improves the club""s feel, and reduces vibration. The present invention satisfies this need and provides further related advantages.
The present invention provides a solution to counteract the negative side effects described above, by allowing club designers to design a club with an optimal center of gravity, while at the same time lowering the stiffness proximate the sole, creating more consistent flex while striking the ball, improving the feel of the club and reducing vibration.
According to a preferred embodiment, a golf club head has a body with a striking face, a rear cavity, a hosel and a sole portion. The rear cavity has a cavity wall and a cavity rim, and a recess having a wall is formed proximate the rear cavity. The recess extends generally from the rear cavity toward a bottom of the sole portion. An insert is located within the recess and includes a core and an intermediate layer that at least partially separates the core from the recess wall. The intermediate layer has a hardness and a modulus of elasticity that are less than that of the core, such that when the golf club head is used to strike a golf ball, the resulting vibrations are dissipated by compression of the intermediate layer and friction between the core and the intermediate layer.
In another preferred embodiment, a golf club head has a body with a striking face, a rear cavity and a sole portion. A recess is formed in the rear cavity and extends generally toward a bottom of the sole portion. There is at least one aperture formed proximate the recess and extending generally from the recess toward the bottom of the sole portion. A cell is inserted within the aperture and has a pin and an outer sleeve. The sleeve has a hardness and a modulus of elasticity that are less than that of the pin, such that when the golf club head is used to strike a golf ball, the resulting vibrations are dissipated by compression of the sleeve and friction between the pin and the sleeve.
Yet another preferred embodiment includes a main body having a front perimeter, a hosel, a rear portion forming a rear cavity and a sole portion. A first recess is formed in the sole portion and extends generally from the rear cavity toward a bottom of the sole portion. The first recess has a recess wall. A striking face is attached to the front perimeter of the main body, and a hollow portion is formed between the striking face and a wall of the rear cavity. A core and an intermediate layer are located within the first recess, with the intermediate layer at least partially separating the core from the recess wall. A weight is located in the sole portion having a density greater than or equal to a density of the core. The intermediate layer has a hardness and a modulus of elasticity that are less than that of the core, such that when the golf club head is used to strike a golf ball, the resulting vibrations are dissipated by compression of the intermediate layer.
For purposes of summarizing the invention and the advantages achieved over the prior art, certain advantages of the invention have been described herein above. Of course, it is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.
All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed.